**Background:** Microalgae are aquatic unicellular microorganisms with high protein content, essential amino acids, pigments, lipids, sterols, polysaccharides, vitamins, and phenolic compounds. Despite their nutritional and functional potential—including antioxidant, immunomodulatory, and anticancer properties—commercial uptake is limited by unpleasant green color, fishy flavor, and poor digestibility due to complex cell walls. This review provides a comprehensive discussion of bioprocesses optimized for microalgal production and utilization in the food industry.
**Methods:** The authors conducted a narrative review of the literature, covering regulatory aspects (EU Novel Food Regulation 2015/2283, FDA GRAS status), production systems (open ponds vs. closed bioreactors), harvesting techniques (filtration, centrifugation, flocculation), drying methods (freeze-drying, spray-drying, drum drying, sun-drying), and bioprocessing strategies including metabolite extraction, enzymatic treatments, fermentation, and microencapsulation. The review also surveys studies on microalgae incorporation into bread, baked goods, beverages, soups, snacks, pasta, and dairy products.
**Key Results:** Freeze-drying showed the lowest protein loss (>90% retained), while convective, oven, infrared, and spray drying resulted in 10–25% protein losses. Lyophilized Spirulina showed increased peptides and amino acids (up to 180 mg g⁻¹ combined) compared to wet biomass. Protein digestibility varies greatly among species: A. platensis, Chlorella vulgaris, and Chlorella sorokiniana showed the highest values, while Tetraselmis suecica, Phaeodactylum tricornutum, and Porphyridium purpureum were least digestible. Enzymatic hydrolysis with Alcalase® gave the highest extraction yield of hydrophilic compounds and released the antioxidant peptide VTAGLVGGGAGK with EC50 values of 1.08 mg mL⁻¹ (ABTS), 1.35 mg mL⁻¹ (hydroxyl radical), and 1.24 mg mL⁻¹ (ferrous ion chelation). Lactic acid fermentation with L. plantarum increased DPPH radical scavenging activity to nearly 80% and phenolic content from 4.5 to 18.9 mg g⁻¹ gallic acid equivalents after 48 hours. Bread fortified with 1–5% Spirulina showed up to 39% more protein than control. Cookies with 2–6% microalgae showed high color stability. Fermented Chlorella in pig diets improved growth performance and reduced E. coli shedding. Between 2015 and 2019, approximately 13,090 new food and beverage products containing algal ingredients were launched globally (5720 in Europe), with 79% in foods and 21% in beverages.
**Clinical Implications:** Microalgae offer a sustainable protein source with bioactive compounds that may support cardiovascular health, glycemic control, and antioxidant defense. However, the authors emphasize that most evidence comes from in vitro studies; in vivo and clinical data on protein digestibility, bioavailability, and physiological effects are lacking. Bioprocessing technologies—particularly fermentation and enzymatic treatments—can enhance functional properties (antioxidant, antimicrobial, anti-hypertensive) while mitigating sensory drawbacks, but cost-effectiveness and scalability remain challenges. The review calls for more research on whole-biomass bioprocessing, ex vivo and in vivo digestibility studies, and development of products for specific consumer niches such as sports nutrition.